Fluid impingement starter for turbine engines



Nov. 21, 1961 P. R. PAIEMENT 3,009,320

FLUID IMPINGEMENT STARTER FOR TURBINE ENGINES 2 SheetsSheet 1 Filed June15. 1959 flew i arraeuer- Nov. 21, 1961 P. R. PAIEMENT 3,009,320

FLUID IMPINGEMENT STARTER FOR TURBINE ENGINES 2 Sheets-Sheet 2 FiledJune 15. 1959 JNVENTOR. PM! /P E. Pfl/EME/V 7' United h I 3,009,320Patented Nov. 21, 1961 3,009,320 FLUID D/IPINGEMENT STARTER FOR TURBINEENGINES Philip Raymond Iaiernent, Melrose, Mass, assignor to GeneralElectric Company, a corporation of New York Filed June 15, 1959, Ser.No. 820,412 9 Claims. (Cl. 6039.14)

This invention relates to fluid impingement starters for turbineengines, and particularly to an improved retractable fluid nozzle foruse in such starters.

Fluid impingement starters are widely utilized in turbine engines.According to present practice, a high pressure fluid is usually impingedupon the buckets of a turbine Wheel by means of a nozzle communicatingwith a duct defining a working fluid path through the buckets. Thepressure and velocity of the fluid impinging upon the buckets causes theWheel to rotate at a speed suflicient to induce self-sustainingoperation of the engine.

In order to gain maximum starting effectiveness, it is desirable toplace the starting nozzle between the partitions of the working fluidnozzle customarily located upstream of the turbine wheel, and extendinginto the Working fluid duct, so that the orifice of the starting nozzleis positioned in close proximity to the leading edges of the buckets.

However, such positioning of the starting nozzle within the workingfluid path produces undesirable turbulence of the working fluid streamduring engine operation, with consequent unbalanced vibratory excitationof the turbine buckets. For this reason, starting nozzles of the kinddescribed are generally not allowed to protrude into the working fluidpath, but terminate at the inner surface of the duct defining that path.

It is an object of my invention to provide a fluid impingement starternozzle which is extendable into the working fluid path of an associatedturbine engine for starting operation, and is retractable from that pathduring normal operation of the engine.

It is a further object of my invention to provide means forautomatically extending such a starter nozzle into the working fluidpath upon commencement of the starting operation.

It is still a further object of my invention to provide means forautomatically retracting such a starter nozzle from the working fluidpath upon completion of the start ing operation, as the operation of theassociated turbine engine becomes self-sustaining.

Other objects and advantages of my invention will become apparent as thedescription proceeds.

Briefly stated, in accordance with one aspect thereof, my invention maybe carried out in a preferred embodiment by providing a starter nozzlebody which is slidable in a nozzle housing mounted in an opening in theworking fluid duct of a turbine engine, so that the nozzle body may beextended into and retracted from the working fluid path. The housing ispreferably positioned in an opening in a nozzle diaphragm placedupstream of the turbine wheel, and is mounted at such an angle that thenozzle body impinges starting fluid directly upon the leading edges ofthe turbine buckets when in the extended position. The nozzle body andhousing are formed as a double-acting piston and cylinder having meansto limit relative motion in either direction. Starting fluid of suitablepressure is supplied to the nozzle body through the housing from anydesired source, and this fluid acts upon the body to automatically causeits extension into the working fluid path and toward the turbinebuckets. As the turbine engine reaches a se1f-sustaining operatingspeed, the supply of starting fluid is shut oli, and compressed air bledfrom nor of duct 4 forming the working fluid path of the engine.

a turbine-driven compressor is supplied to the housing to automaticallyretract the nozzle body from the working fluid stream.

In alternative embodiments, extension and/ or retraction of the nozzlefrom the interior of the Working fluid duct is performed by means of amechanically operated rod, which is actuated by any desired meansforming no part of this invention. Mechanical actuating means may becombined with either of the fluid pressure actuating means of thepreferred embodiment previously described, as desired in particularapplications.

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter which I regard as myinvention, it is believed that the invention will be more clearlyunderstood from the following description of a preferred and severalalternative embodiments, referring to the drawings, in which:

FIG. 1 is a cross-sectional elevation of a preferred embodiment of myimproved nozzle construction in a retracted position, showing a portionof an associated turbine engine, as viewed in a plane passing radiallythrough the centerline of the engine;

FIG. 2 is a view similar to FIG. 1, but showing the nozzle in anextended position for a starting cycle;

FIG. 3 is a view taken along the line 3-3 in FIG. 1, looking radiallyinto the engine, partially in section;

FIG. 4 is a pictorial view of the nozzle body of FIG. I, removed fromthe engine;

FIG. 5 is a cutaway pictorial view of the nozzle housing of FIG. 1,removed from the engine;

FIG. 6 is across-sectional elevation of an alternative embodiment of myinvention in a retracted position, showing a portion of an associatedturbine engine;

FIG. 7 is a view similar to FIG. 6, but showing the nozzle in anextended position for a starting cycle;

FIG. 8 is a cross-sectional elevation of a further alternativeembodiment of my invention in an extended position for a starting cycle;and

FIG. 9 is a cross-sectional elevation of a still further embodiment ofmy invention in an extended position for a starting cycle.

Referring to FIGS. 1, 2 and 3, a preferred embodiment of my improvedretractable nozzle is shown in operative relationship with a portion ofan associated turbine engine generally designated 1. The engine includesa rotatably mounted turbine wheel 2, carrying a row of buckets 3 on itsperiphery. In conventional manner, air is taken from the atmosphere andcompressed by a compressor (not shown) connected to be driven by turbinewheel 2, passed to fuel combustion means (not shown), and the resultingworking fluid is delivered to buckets 3 through a duct generallydesignated 4, which defines the working fluid path of the engine. Only aportion of duct 4 is shown, comprising a composite nozzle ring 5, anozzle shroud ring 6, and a turbine shroud ring 7. Working fluid passesto buckets '3 through duct 4 in the direction shovm by the arrow inFIG. 1. As a result, buckets 3 and wheel 2 are rotated in the directionshown by the arrow in FIG. 3, driving the compressor during operation ofthe engine. Rings 5 and 6 are secured to a row of nozzle partitions 8,forming a nozzle diaphragm for directing working fluid at the mostfavorable entrance angle into buckets 3. A portion of the outer enginecasing is shown at 9. The turbirle engine is of a well known typeforming no part of the present invention, and will not be furtherdescribed.

To provide improved means in accordance with my invention for startingthe engine, a nozzle body 12 is slidably mounted within a nozzle housing'13. Housing 13 is inserted through openings 14, 15 and 16, formed incasing 9 and in the members of composite ring 5, respectively, so thatthe housing communicates at one end with the inte- Inner end 17 of thehousing is faired into the inner surface of composite ring 5, to avoidinterference with the working fluid stream. The housing is welded orotherwise secured in fluid-sealing engagement with casing 9 and ring 5.

Any suitable source of compressed starting fluid (not shown) may beused, such as an air bottle, or a compressor carried by a ground cart.The starting fluid is admitted to housing 13 and body 12 through aconduit 18 and a manifold 19, arranged in serial flow relation andsecured together in fluid-tight relationship by welding or othersuitable means. A valve 20 of any desired type is placed in series flowrelation in conduit 18 for controlling admission of starting fluid tomanifold 19. The manifold is shown extended circumferentially about theengine, so that a plurality of starting nozzles may be provided, asdesired.

Referring now to FIGS. 4 and 5, housing 13 is formed with an internalbore 24, and an internal flange 25 near end 17. Body 12 is formed with astarting fluid passage 26 therethrough. The body is also formed with acircumferential flange 27 at one end, and is received in slidingengagement by bore 24 and flange 25 within housing 13. A fluid-confiningcylinder 28 (see FIG. 1) of variable volume is thus formed between thehousing and body, the confronting annular faces of flanges 25 and 27comprising pressure reaction surfaces in the cylinder.

Housing '13 is also formed with a plurality of stop lugs 29 spaced aboutbore 24 and spaced longitudinally from flange 25. A radial opening 30 isformed through a wall of the housing between flange 25 and stop lugs 29.

Body 12 is assembled in bore 24 at end 32 of the housing, and theassembly is secured by means of a snap ring 33 secured in a notch 34near the end of the bore. Snap ring 33 and stop lugs 29 thus limit thetravel of flange 27 and body 12 relative to housing 13.

Referring again to FIGS. l-3, cylinder 28 is connected in fluid flowrelation through opening 30 and a tube 36 with a compressor bleed tube37. Tube 37 is connected with the engine compressor (not shown) tosupply pressurized air to cylinder 28 during operation of turbine engine1.

In operation, valve 20 is opened to begin a starting cycle. Pressurizedstarting fluid is admitted from conduit 18 to manifold 19, and thence tobore 24 of housing 13 and passage 26 of body 12. The unbalanced reactionof the starting fluid upon the reaction surface formed by flange 27 ofbody 13 drives the body from the retracted position of FIGS. 1 and 3 tothe extended position of FIG. 2, also shown in dotted lines at 12 inFIG. 3. The reaction is unbalanced because atmospheric pressure prevailsin compressor bleed tube 37 and cylinder 28, the compressor beingstationary and inoperative at this time. Nozzle body 12 is thusautomatically driven by admission of the starting fluid to its extendedposition in the interior of duct 4. Its motion is halted by lugs 29 asit reaches close proximity to the leading edges of buckets 3. Startingfluid issues through passage 26 directly upon buckets 3, in thedirection shown by the arrows, causing their rotation with maximumeffectiveness.

As buckets 3 and turbine wheel 2 increase in rotational speed, theengine compressor supplies compressed air to the fuel combustion means,and combustion is initiated in a conventional manner. As the operationof the engine becomes self-sustaining, and valve 20 is closed todiscontinue the supply of starting fluid to the engine, the meanspreviously described provide for automatic retraction of nozzle body 12from the extended position of FIG. 2. Referring to FIG. 1, compressedair flows in tubes 37 and 36 in the direction shown by the arrows and isreceived by cylinder 28 through opening 30 from the engine compressor,as the engine accelerates to operational speed. This pressure producesan unbalanced reaction upon the confronting reaction surfaces of flanges25 and 27, urging body 12 from the extended position of FIG. 2 to theretracted position of FIG. 1. Snap ring 33 stops the motion of the bodyin this position, and it is retained in place during operation of theengine by a continued supply of air from compressor bleed tube 37.

An alternative embodiment of my invention is shown in FIGS. 6 and 7. Theturbine engine associated with the starter nozzle is substantially thesame as that shown in the embodiment of FIGS. 1-3, and will not befurther described; similar parts of the engine are similarly numbered,but with the subscript a. In this embodiment, a nozzle housing 40 isitself radially slidable in openings 41, 42 and 43 of casing 9a and themembers of composite nozzle ring 5a, respectively. An inner end 44 ofhousing 40 is faired into the inner surface of ring 5a, to avoidinterference with the working fluid stream when in the retractedposition of FIG. 6.

Mechanical means are provided for extending and retracting the housinginto the interior of duct 4a, comprising a rod 45 threaded at an end 46into housing 40. The rod may be operated manually, or may be actuated bymechanical means of any suitable type, forming no part of thisinvention.

A nozzle body 48 is slidably mounted in a bore 49 of housing 40. Body 48includes a starting fluid passage 50, and a flange 51 formed about anend thereof. A stop flange 52 is formed within bore 49 of the housing tolimit motion of body 48 into the bore by interference with flange 51.

Following insertion of body 48 into bore 49, a snap ring 54 is insertedin a groove 55, formed about bore 49 and spaced from an end thereof.Ring 54 does not form a full circle, but is made with lesser arc lengthin order to permit fluid to flow freely therepast between bore 49 andbody 48. The assembly is completed by a snap ring 56, which is insertedin a groove 57 at an end of bore 49. Ring 56 seals a space furtherdefined by body 43, bore 49, and flange 51 to form a fluid-confiningcylinder 58. Confronting faces of flange 51 and ring 56 form pressurereaction surfaces in cylinder 58.

Starting fluid from any desired source is supplied to bore 49 through aconduit 60, threaded into the bore at 61 and sealed by means of a nut 62threaded on the conduit. A compressor bleed tube 63 is placed in fluidcommuuication with cylinder 58 through a bore 64 formed in body 40. Bore64 forms an opening 65 in the wall of bore 49, spaced between rings 54and 56. Tube 63 is threaded into bore 64 and 66, and is sealed by meansof a nut 67 threaded on the tube.

To initiate the starting operation, rod 45 is actuated to extend housing40 into the position of FIG. 7 in the interior of duct 4a. Startingfluid is then admitted to bore 49 and passage 50 of body 48 throughconduit 60, in the direction shown by the arrows in FIG. 7. The startingfluid produces an unbalanced reaction upon the reaction surface formedby flange 51, driving it to the right as viewed in FIG. 7. The pressurein cylinder 58 at this time is atmospheric, the engine compressor beingstationary.

The movement of body 48 is halted by ring 54 in the position of FIG. 7,and the starting fluid is directly impinged upon buckets 3a to obtainmaximum starting effectiveness.

As buckets 3a and the associated engine attain selfsustainingoperational speed, the starting fluid supply is shut off, and compressedair is received in cylinder 58 through tube 63, bore 64, and opening 65from the engine compressor, in the direction shown by the arrows in FIG.6. The unbalanced reaction upon the reaction surface formed by flange 51drives body 48 to the left as viewed in FIG. 6. The movement of body 48is halted by flange 52 in the position of FIG. 6, and rod 45 may then beactuated to withdraw housing 40 from the working fluid stream in theinterior of duct 4a.

A further embodiment is shown in FIG. 8, in an extended position for astarting operation. The components of the associated turbine engine aresimilar, and are similarly numbered, with subscripts b. In thisinstance, the nozzle housing is eliminated as a separate element. Anozzle body 70 is provided, which is radially slidable in openings 71,72 and 73 formed in casing 9b and composite ring 5b, respectively.Mechanical means are provided for actuating the nozzle body, comprisinga rod 74, which may be operated manually or by any desired mechanism.Rod 74 is secured to body 70 by means of a bracket 75, fastened bywelding or other suitable means. Rod 74 may be used both for extendingand withdrawing body 70 in duct 4b; however, body '70 is formed to beautomatically extended by the admission of starting fluid thereto, androd 74 need not be actuated to perform this function.

In order to provide for its automatic extension upon initiation of thestarting cycle, body 70 is formed with a curved fluid passage 76terminated in an end wall 77 and an orifice 78. A starting fluid conduit79 is slidably received in passage 76. As starting fluid is admitted topassage 76 in the direction shown by the arrows to commence a startingcycle, the unbalanced reaction of the starting fluid upon the reactionsurface formed by end wall 77 drives body 70 radially inwardly in duct41;. This motion is limited to the position of FIG. 8 by the abutment ofbracket 75 upon casing 9b. Starting fluid is ejected from orifice 78directly and in close proximity upon buckets 3b, again providing astarting operation of maximum effectiveness. As engine 112 reachesself-sustaining operational speed, body 70 is withdrawn from theinterior of duct 4b by means of rod 74.

Still a further embodiment is shown in FIG. 9. The parts of theassociated engine are similar, and are similarly numbered, withsubscripts c. In this instance, extension and withdrawal of an arcuatenozzle body 80 are again automatically performed. Nozzle body 80 isprovided with stop flanges 81 and 82 at the ends thereof, and with astarting fluid passage 83 terminating in an orifice 84. T facilitateassembly, flange 82 is formed as a separate ring, and is threaded onbody 80 after assembly of the nozzle. Flange 81 is slidably received influid-sealing relation within an arcuate bore 85 of a nozzle housing 86.

Housing 86 is formed with at least one stop lug 89 spaced longitudinallyalong bore 85, to permit fluid flow therepast, while limiting movementof body 80 by interfering with flange 81. Housing 86 is further formedwith a flange 90 at its inner end, faired into ring c and slidablyengaging body 80 in fluid-sealing relationship. A fluidconfiningcylinder 91 is thus formed between housing 86 and body 80, havingconfronting faces of flanges 90 and 81 as pressure reaction surfaces.

A starting fluid manifold 92 is connected in serial flow relation withbore 85 of housing 86 through a suitable Valve 93. A compressor bleedtube 94 is connected in serial flow relation with cylinder 91 through anopening 95 in housing 86, being secured in the opening by welding orother suitable means.

Operation is similar to that of the embodiment shown in FIGS. 1-5. Tocommence a starting cycle, valve 93 is opened to admit starting fluidfrom manifold 92- to bore 85 of housing 86 and passage 83 of body 80, inthe direction shown by the arrows. The unbalanced reaction of thestarting fluid upon the reaction surface formed by flange 81 drives body80 toward the extended position shown in FIG. 9, the motion beinglimited by stop lug 89. The starting fluid then impinges upon buckets 30from orifice 84, bringing the buckets and the engine up toselfsustaining operating speed. The starting fluid flow is then shut oifby closing valve 93. Pressure built up in the engine compressor isreceived in cylinder 91 through tube 94, and the unbalanced reactionupon the reaction surface formed by flange 81 drives body 8%) into theretracted position and out of the working fluid path in duct 40.

It will be apparent from the foregoing description that I have providedan improved retractable fluid impingement starter nozzle for a, turbineengine, having means for automatic extension into a working fluid ductfor starting the engine, and for automatic retraction from the workingfluid duct during operation of the engine to avoid interference with theflow of working fluid in the duct. It will also be apparent that myinvention encompasses the use of alternative mechanical means forextending and retracting the starter nozzle, alone or in combinationwith automatic means. -It should be understood that my invention is notlimited to specific details of construction and arrangement thereofherein illustrated, and that modifications may occur to those skilled inthe art without departing from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. A fluid impingement starter for use in turbine engines of the typecomprising a working fluid duct and a turbine Wheel rotatably mounted insaid duct; said starter comprising nozzle means including an extensiblenozzle body movable into and out of the interior of said duct through anopening formed therein, said nozzle body formed with a fluid passage,and means for moving said nozzle body into an extended position in saidduct for impinging a stream of starting fluid through said fluid passageupon said turbine wheel and for moving said nozzle body from theinterior of said duct into a retracted position during operation of saidturbine engine.

2. A fluid impingement starter for use in a turbine engine of the typecomprising a working fluid duct and a turbine wheel rotatably mounted insaid duct; said starter comprising a nozzle housing communicating withsaid duct through an opening formed therein, an extensible nozzle bodyreceived in said housing, said body formed with a fluid passage, meansfor extending said nozzle body into said duct for impinging a stream ofstarting fluid from said fluid passage upon said turbine wheel, andmeans for retracting said nozzle body from said duct during operation ofsaid turbine engine.

3. A fluid impingement starter for use in a turbine engine of the typecomprising a working fluid duct and a turbine wheel rotatably mounted insaid duct; said starter comprising a nozzle body movable into and out ofthe interior of said duct through an opening formed therein, means formoving said body out of said duct.

to a retracted position during operation of said engine, said bodyformed with a reaction surface and with a fluid passage, a manifold influid communication with said fluid passage, and means for admittingstarting fluid to said manifold for starting said engine; wherebystarting fluid acts upon said reaction surface to move said body to anextended position in the interior of said duct for impinging a stream ofstarting fluid from said fluid passage upon said tunbine wheel.

4. A fluid impingement starter for use in a turbine engine of the typecomprising a working fluid duct and a turbine wheel rotatably mounted insaid duct; said starter comprising a nozzle housing communicating withthe interior of said duct through an opening formed therein, a nozzlebody slidably mounted in said housing, means for moving said body out ofsaid duct to a retracted position in said housing during operation ofsaid engine, said nozzle body formed with a pressure reaction surfaceand with a fluid passage, and means for admitting starting fluid to saidpassage; starting fluid admitted to said passage producing an unbalancedreaction upon said surface to extend said body from said housing intosaid duct for impinging a stream of starting fluid from said passageupon said turbine Wheel.

5. A fluid impingement starter as recited in claim 4, in which saidnozzle housing is slidably received in said duct, together with meansfor moving said housing into and out of the interior of said duct.

6. A fluid impingement starter for use in a turbine engine of the typecomprising a Working fluid duct and a turbine wheel rotatably mounted insaid duct; said starter comprising a nozzle body movable into and out ofthe interior of said duct through an opening formed therein, said bodyformed with a fluid passage and with a circumferential flange, means formoving said body into an extended position in the interior of said ductfor impinging a stream of starting fluid from said fluid passage uponsaid turbine wheel, and tube means for supplying compressed fluid tosaid circumferential flange to retract said body from the interior ofsaid duct during operation of said turbine engine.

7. A fluid impingement starter as recited in claim 6, together with anozzle housing, said body slidable in said housing, said housing andsaid body cooperating to form a fluid-confining cylinder partiallydefined by said circumferential flange, said tube means supplyingcompressed fluid to said cylinder to retract said body from the interiorof said duct during operation of said turbine engine.

8. A fluid impingement starter for use in a turbine engine of the typecomprising a Working fluid duct and a turbine wheel rotatably mounted insaid duct; said starter comprising a nozzle housing communicating withthe interior of said duct through an opening formed therein, a nozzlebody formed with a reaction surface and with a fluid passage, said bodyslidably mounted in said housing for movement into said duct to anextended position for impinging a stream of starting fluid from saidpassage upon said turbine wheel and out of said duct to a retractedposition, said housing and body cooperating to form a fluid-confiningcylinder, tube means for supplying compressed fluid to said cylinder tomove said nozzle body from the interior of said duct to said retractedposition during operation of said turbine engine, and means foradmitting starting fluid to said fluid passage for starting said engine,whereby starting fluid acts upon said reaction surface of said body tomove said body to said extended position.

9. A fluid impingement starter, as recited in claim 8, in which saidnozzle housing is slidably received in said duct, together with meansfor moving said housing into and out of the interior of said duct.

References Cited in the file of this patent UNITED STATES PATENTS2,714,802 Wosika Aug. 9, 1955 2,929,206 Davenport Mar. 22, 1960 FOREIGNPATENTS 1,076,691 France Apr. 21, 1954

